gatsby-node.js

const path = require(`path`)

exports.onCreateWebpackConfig = ({ stage, loaders, actions }) => {
  if (stage === 'build-html') {
    actions.setWebpackConfig({
      module: {
        rules: [
          {
            test: /p5/,
            use: loaders.null()
          }
        ]
      }
    })
  }
}

exports.createSchemaCustomization = ({ actions }) => {
  const { createTypes } = actions
  const typeDefs = `
    type MarkdownRemark implements Node {
      frontmatter: Frontmatter
    }
    type Frontmatter {
      photos: [String]
      widePhotos: [String]
      fullWidthPhotos: [String]
    }
  `
  createTypes(typeDefs)
}

exports.createPages = async ({ actions, graphql, reporter }) => {
  const { createPage } = actions

  const eventTemplate = path.resolve(`src/templates/eventTemplate.js`)

  const result = await graphql(`
    {
      allMarkdownRemark(
        sort: { order: DESC, fields: [frontmatter___date] }
        limit: 1000
      ) {
        edges {
          node {
            id
            parent {
              ... on File {
                name
              }
            }
          }
        }
      }
    }
  `)

  if (result.errors) {
    reporter.panicOnBuild(`Error while running GraphQL query.`)
    return
  }

  result.data.allMarkdownRemark.edges.forEach(({ node }) => {
    createPage({
      path: node.parent.name,
      component: eventTemplate,
      context: {
        id: node.id,
      },
    })
  })
}